My baby does not seem to want to eat any of his first/transition foods

My baby is 6 months old and has an interest in food but when i give him his transition meal he spits it out. When I first gave him mashed pumpkin, he ate it but the second time he did not. I have also given him apples(mashed and steamed), bananas(2 kinds and both were steamed and mashed), Eu Yan Seng brown rice powder (both with and without whitebait powder) but he does not seem to swallow it. Is there any other food options, method of preparation that i could try? I am really getting worried. What should i do? He does drink about 4 or 5 bottles of 240ml formula milk a day and about 100 ml of breast milk 3 times a day. He normally drinks this amount of milk b4 the introduction of food as well. I'm at my wits end. Am going to try mashed avocados next but I'm worried he's not properly eating any solids and that it would impact his growth.